What that image drove home for me is:
1) that DNA transcription isn't something that happens rarely, or once-at-a-time. DNA is constantly being transcribed; proteins are constantly being built. The scale and rate isn't something I'd ever been taught.
2) How RNA polymerase works must be taking into account a hell of a lot of congestion. Polymerase molecules must constantly be bumping into each other.
3) How the picture would make no sense whatsoever unless you already know what the mechanism is.
I think it does make sense to start with the idealised process, as long as you follow up with messy reality.
